Final answer:
Hair color variation in humans is determined by alleles that regulate melanin production and distribution. Blonde hair is a mutation that may have arisen through natural selection in low light conditions. Differences in hair color are not due to a lack of proteins in lighter hair.
Step-by-step explanation:
Hair color variation in humans, such as blonde and darker hair, is predominantly determined by differences in alleles. These alleles control the production and distribution of melanin, the pigment responsible for hair color. Individuals with the MC1R gene variant tend to have lighter hair colors, while those with the normal version of the gene have darker hair.
Blonde hair is considered a mutation and is relatively rare worldwide, occurring more frequently in populations with European ancestry. It is believed that blonde hair arose through natural selection, possibly as an adaptation to low light conditions in northern latitudes.
The differences in hair color are not caused by a lack of proteins in lighter hair, but rather by the genetic variations and expression of genes involved in melanin production and distribution.
Learn more about Hair color variation in humans